Normal speech production is relegated to near automaticity and is dependent upon a highly coordinated coupling of motor output with sensory input from auditory and somatosensory (i.e., sensory inputs from skin, mucosa, muscle and joint receptors) systems. Models of sensorimotor dysfunction, such as Parkinson's disease (PD), demonstrate substantially impoverished sensorimotor integration and degradation of motor control; however, few studies have examined the relationship between changes in sensorimotor integration with speech motor control in diseases such as PD. This study will use laryngeal sensory detection thresholds and laryngeal aerodynamics to examine the relationship between sensorimotor integration and control of speech-related laryngeal movements in a group of patients with idiopathic Parkinson's disease and a group of normal controls. The specific aims of this study address three questions: (1) Do individuals with PD exhibit different timing of vocal fold medialization than normal controls? (2) Do individuals with PD exhibit different laryngeal sensory detection thresholds than normal controls? (3) What is the relationship between timing of vocal fold medialization and laryngeal sensory detection thresholds? The long-term goal is to improve our understanding of the role of somatosensory input in the precision of speech-related laryngeal movements and how these precise movements are disrupted by changes in sensory integration.